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    Mathematical Model for Diabetes Mellitus with Impulsive Injections of Glucose-insulin
    WANG Xia, ZHANG Ying, SONG Xin-yu
    Chinese Quarterly Journal of Mathematics    2017, 32 (2): 118-133.   DOI: 10.13371/j.cnki.chin.q.j.m.2017.02.002
    Abstract139)      PDF(pc) (1111KB)(239)       Save
    Impulsive injections of glucose and insulin analogues are very important strategies for the control of diabetes mellitus. We mainly imitate diabetes patients take insulin before eating, and eating approximately as a pulse blood glucose injection, as a result, a new mathematical model with impulsive injections of both glucose and insulin at different fixed times is formulated in this paper. Using the discrete dynamical system determined by the stroboscopic map, we show that the existence and uniqueness of a positive globally asymptotically stable periodic solution for type I diabetes. By impulsive comparison theorem, we obtain the glucose concentration level of the system is uniformly bounded above and below for type Ⅱ diabetes. Numerical analysis verifies our theoretical results. 
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    Well-posedness for A Plat Equations with Nonlocal Source Term
    LIU Gong-wei, ZHAO Rui-min, ZHANG Hong-wei
    Chinese Quarterly Journal of Mathematics    2019, 34 (4): 331-342.   DOI: 10.13371/j.cnki.chin.q.j.m.2019.04.001
    Abstract105)      PDF(pc) (757KB)(137)       Save
    In this paper,we investigate the initial boundary value problem for a plate equation with nonlocal source term.The local,global existence and exponential decay result are established under certain conditions.Moreover,we also prove the blow-up in finite time and the lifespan of solution under certain conditions. 
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    Asymptotic Property of Solutions in a 4th-Order Parabolic Model for Epitaxial Growth of Thin Film#br#
    SUN An-qi, LI Feng-jie
    Chinese Quarterly Journal of Mathematics    2022, 37 (2): 162-177.   DOI: 10.13371/j.cnki.chin.q.j.m.2022.02.006
    Abstract79)      PDF(pc) (421KB)(56)       Save
    This paper deals with a homogeneous Neumann initial-boundary problem of
    a 4th-order parabolic equation modeling epitaxial growth of thin film. We determine the
    classification of initial energy on the existence of blow-up, global existence and extinction
    of solutions by using the potential well method and the auxiliary function method.
    Moreover, asymptotic estimates on global solution and extinction solution are studied,
    respectively.
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    Italian Domination of Strong Product of Two Paths
    WEI Li-yang, LI Feng
    Chinese Quarterly Journal of Mathematics    2024, 39 (3): 221-234.   DOI: 10.13371/j.cnki.chin.q.j.m.2024.03.001
    Abstract26)      PDF(pc) (392KB)(19)       Save
    The domination problem of graphs is an important issue in the field of graph theory. This paper mainly considers the Italian domination number of the strong product between two paths. By constructing recursive Italian dominating functions, the upper bound of its Italian domination number is obtained, and then a partition method is proposed to prove its lower bound. Finally, this paper yields a sharp bound for the Italian domination number of the strong product of paths.
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    Factorized Smith Method for A Class of High-Ranked Large-Scale T-Stein Equations
    LI Xiang, YU Bo, TANG Qiong
    Chinese Quarterly Journal of Mathematics    2024, 39 (3): 235-249.   DOI: 10.13371/j.cnki.chin.q.j.m.2024.03.002
    Abstract15)      PDF(pc) (11638KB)(13)       Save
    We introduce a factorized Smith method (FSM) for solving large-scale highranked J-Stein equations within the banded-plus-low-rank structure framework. To effectively reduce both computational complexity and storage requirements, we develop techniques including deflation and shift, partial truncation and compression, as well as redesign the residual computation and termination condition. Numerical examples demonstrate that the FSM outperforms the Smith method implemented with a hierarchical
    HODLR structured toolkit in terms of CPU time.
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    On the Method of Solution for the Non-Homogeneous Generalized Riemann-Hilbert Boundary Value Problems
    ZHANG Wen-wen, LI Ping-run
    Chinese Quarterly Journal of Mathematics    2024, 39 (3): 262-269.   DOI: 10.13371/j.cnki.chin.q.j.m.2024.03.004
    Abstract29)      PDF(pc) (321KB)(17)       Save
    This paper studies the non-homogeneous generalized Riemann-Hilbert (RH) problems involving two unknown functions. Using the uniformization theorem, such problems are transformed into the case of homogeneous type. By the theory of classical boundary value problems, we adopt a novel method to obtain the sectionally analytic solutions of problems in strip domains, and analyze the conditions of solvability and properties of solutions in various domains.
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    Pseudo S-Asymptotically (ω,c)-Periodic Solutions to Fractional Differential Equations of Sobolev Type
    MAO Hang-ning, CHANG Yong-kui
    Chinese Quarterly Journal of Mathematics    2024, 39 (3): 295-306.   DOI: 10.13371/j.cnki.chin.q.j.m.2024.03.007
    Abstract24)      PDF(pc) (402KB)(9)       Save
    In this paper, we firstly recall some basic results on pseudo S-asymptotically (ω,c)-periodic functions and Sobolev type fractional differential equation. We secondly investigate some existence of pseudo S-asymptotically (ω,c)-periodic solutions for a semilinear fractional differential equations of Sobolev type. We finally present a simple example.
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    Updating Mass and Stiffness Matrices Using Eigenstructure Assignment Methods
    LIU Li-na, YUAN Yu-ying, YUAN Yong-xin
    Chinese Quarterly Journal of Mathematics    2021, 36 (4): 419-429.   DOI: 10.13371/j.cnki.chin.q.j.m.2021.04.009
    Abstract74)      PDF(pc) (285KB)(99)       Save
    A novel numerical method is presented to update mass and stiffness matrices simultaneously with measured vibration data by means of the combined acceleration and displacement output feedback. By the method, the required displacement and acceleration output feedback gain matrices are determined, and thus the optimal approximation mass matrix and stiffness matrix which satisfy the required orthogonality relation and eigenvalue equation are found. The proposed method is computationally efficient and the updated mass and stiffness matrices are also symmetric and have the compact expressions. The numerical example shows that the proposed method is reliable and attractive.
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    Majority Coloring of r-Regular Digraph
    XIA Wei-hao, SHI Mei, XIAO Ming-yue, CAI Jian-sheng, WANG Ji-hui
    Chinese Quarterly Journal of Mathematics    2022, 37 (2): 142-146.   DOI: 10.13371/j.cnki.chin.q.j.m.2022.02.004
    Abstract218)      PDF(pc) (330KB)(357)       Save
     A majority k-coloring of a digraph D with k colors is an assignment c: V ( D ) →{ 1,2,···,k} , such that for every v∈V (D), we have c(w)=c(v) for at most half of all out-neighbors w∈N+( v ). For a natural number k≥2, a
    1/k-majority coloring of a digraph is a coloring of the vertices such that each vertex receives the same color as at
    most a 1/proportion of its out-neighbours. Kreutzer, Oum, Seymour, van der Zypen and
    Wood proved that every digraph has a majority 4-coloring and conjectured that every
    digraph admits a majority 3-coloring. Gir$\widetilde{a}$o, Kittipassorn and Popielarz proved that every
    digraph has a 1/k-majority 2k-coloring and conjectured that every digraph admits a
    1\k-majority (2k−1)-coloring. We showed that every r -regular digraph D with r>36ln(2n)
    has a majority 3-coloring and proved that every digraph D with minimum outdegree
    $\delta^+>\frac{2k^2(2k-1)^2}{(k-1)^2}\ln{[(2k-1)n]}$ has a 1/k-majority (2k−1)-coloring. And we also proved that
    every r-regular digraph D with  $r>\frac{3k^2(2k-1)}{(k-1)^2} \ln(2n)$ has a 1/k-majority (2k−1)-coloring.
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    Adaptive Image Zooming Algorithm Combining Total Variation Minimization and a Second-order Functional
    WANG Yan-yan, GAO Ran, GU Cong
    Chinese Quarterly Journal of Mathematics    2016, 31 (4): 435-440.   DOI: 10.13371/j.cnki.chin.q.j.m.2016.04.013
    Abstract90)      PDF(pc) (588KB)(115)       Save
    An image zooming algorithm by using partial differential equations(PDEs) is proposed here. It combines the second-order PDE with a fourth-order PDE. The combined algorithm is able to preserve edges and at the same time avoid the blurry effect in smooth regions. An adaptive function is used to combine the two PDEs. Numerical experiments illustrate advantages of the proposed model. 
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    Some Applications of Surface Curvatures in Theoretical Physics
    YANG Yi-song
    Chinese Quarterly Journal of Mathematics    2023, 38 (3): 221-253.   DOI: 10.13371/j.cnki.chin.q.j.m.2023.03.001
    Abstract240)      PDF(pc) (496KB)(104)       Save
    In this survey article, we present two applications of surface curvatures in theoretical physics. The first application arises from biophysics in the study of the shape of cell vesicles involving the minimization of a mean curvature type energy called the Helfrich bending energy. In this formalism, the equilibrium shape of a cell vesicle may present itself in a rich variety of geometric and topological characteristics. We first show that there is an obstruction, arising from the spontaneous curvature, to the existence of a minimizer of the Helfrich energy over the set of embedded ring tori. We then propose a scale-invariant anisotropic bending energy, which extends the Canham energy, and show that it possesses a unique toroidal energy minimizer, up to rescaling, in all parameter regime. Furthermore, we establish some genus-dependent topological lower and upper bounds, which are known to be lacking with the Helfrich energy, for the proposed energy. We also present the shape equation in our context, which extends the Helfrich shape equation. The second application arises from astrophysics in the search for a mechanism for matter accretion in the early universe in the context of cosmic strings. In this formalism, gravitation may simply be stored over a two-surface so that the Einstein tensor is given in terms of the Gauss curvature of the surface which relates itself directly to the Hamiltonian energy density of the matter sector. This setting provides a lucid exhibition of the interplay of the underlying geometry, matter energy, and topological characterization of the system. In both areas of applications, we encounter highly challenging nonlinear partial differential equation problems. We demonstrate that studies on these equations help us to gain understanding of the theoretical physics problems considered.
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    Harvesting in a Toxic Predator-Prey Model with Carrying Capacity and Maturation Double Delays
    ZHONG Ying, WEI Yu-ming
    Chinese Quarterly Journal of Mathematics    2023, 38 (4): 331-348.   DOI: 10.13371/j.cnki.chin.q.j.m.2023.04.001
    Abstract112)      PDF(pc) (589KB)(76)       Save
     In this paper, a model of predator-prey with dual delay in maturation and carrying capacity is discussed, in which the past activity of the prey should have an impact on the carrying capacity, the mature prey initiates defense mechanisms to release toxins when subjected to predation, and a commercial harvest of the prey is performed. The stability of the equilibrium of the system in the absence of delay is examined and the optimal harvesting strategy of the model is proven. By investigating the roots of the characteristic equation and applying normalized theory, the properties of the coexistence equilibrium of the system and the conditions for the occurrence of the Hopf bifurcation in the neighborhood of the positive equilibrium are described for various combinations of delays. In the end, numerical simulations are used to verify theoretical analysis results.
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    Normalized Ground State Solutions of Nonlinear Choquard Equations with Nonconstant Potential
    LI Nan, ZHAO Hui-yan, XU Li-ping
    Chinese Quarterly Journal of Mathematics    2024, 39 (3): 250-261.   DOI: 10.13371/j.cnki.chin.q.j.m.2024.03.003
    Abstract21)      PDF(pc) (425KB)(9)       Save
     In this paper, we mainly focus on the following Choquard equation......
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    The Existence of Solutions for Kirchhoff-Type Equations with General Singular Terms
    WANG Ji-nan, SUN Da-wei
    Chinese Quarterly Journal of Mathematics    2024, 39 (3): 315-323.   DOI: 10.13371/j.cnki.chin.q.j.m.2024.03.009
    Abstract18)      PDF(pc) (314KB)(7)       Save
    We study the existence of solutions for Kirchhoff-type equations. Firstly, we use the Sobolev inequality and the weakly lower semi-continuity of the norm to prove that the corresponding function can reach the global minimum. Then, we use the variational method and some analytical techniques to obtain the existence of the positive solution of the equation when λ is small enough.
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    General Energy Decay of Solutions for A Wave Equation with Nonlocal Nonlinear Damping and Source Terms
    ZHANG Hong-wei, LI Dong-hao, HU Qing-ying
    Chinese Quarterly Journal of Mathematics    2020, 35 (3): 302-310.   DOI: 10.13371/j.cnki.chin.q.j.m.2020.03.005
    Abstract169)      PDF(pc) (473KB)(353)       Save
    We consider a wave equation with nonlocal nonlinear damping and source terms. We prove a general energy decay property for solutions by constructing a stable set and using the multiplier technique. The main difficult is how to handle with the nonlocal nonlinear damping term. Our result extends and improves the result in the literature such as the work by Jorge Silva and Narciso(Evolution Equation and Control Theory, 2017(6):437-470) and Narciso(Evolution Equations and Control Theory, 2020, 9(2): 487-508).
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    Cyclic Codes over F2 + uF2 + vF2
    LIU Xiu-sheng, LIU Hua-lu
    Chinese Quarterly Journal of Mathematics    2014, 29 (2): 189-194.   DOI: 10.13371/j.cnki.chin.q.j.m.2014.02.005
    Abstract56)      PDF(pc) (295KB)(150)       Save
    We study the structure of cyclic codes of an arbitrary length n over the ring F2+ uF2+ vF2, which is not a finite chain ring. We prove that the Gray image of a cyclic code length n over F2+ uF2+ vF2 is a 3-quasi-cyclic code length 3n over F2
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    A Cubic Systen Which Generates Bargmann Poteutial and N-gap Potential
    CAO Ce-wen
    Chinese Quarterly Journal of Mathematics    1988, 3 (1): 90-96.  
    Abstract65)      PDF(pc) (335KB)(209)       Save
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    A Posterior Estimates in the Finite Element Methods
    E Wei-nan, MU Mo, HUANG Hong-ci
    Chinese Quarterly Journal of Mathematics    1988, 3 (1): 97-107.  
    Abstract715)      PDF(pc) (588KB)(381)       Save
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    Nested Alternating Direction Method of Multipliers to Low-Rank and Sparse-Column Matrices Recovery
    SHEN Nan , JIN Zheng-fen , WANG Qiu-yu
    Chinese Quarterly Journal of Mathematics    2021, 36 (1): 90-110.   DOI: 10.13371/j.cnki.chin.q.j.m.2021.01.007
    Abstract367)      PDF(pc) (427KB)(401)       Save
    The task of dividing corrupted-data into their respective subspaces can be well
    illustrated, both theoretically and numerically, by recovering low-rank and sparse-column
    components of a given matrix. Generally, it can be characterized as a matrix and a
    `2,1-norm involved convex minimization problem. However, solving the resulting problem
    is full of challenges due to the non-smoothness of the objective function. One of the
    earliest solvers is an 3-block alternating direction method of multipliers (ADMM) which
    updates each variable in a Gauss-Seidel manner. In this paper, we present three variants
    of ADMM for the 3-block separable minimization problem. More preciously, whenever
    one variable is derived, the resulting problems can be regarded as a convex minimization
    with 2 blocks, and can be solved immediately using the standard ADMM. If the inner
    iteration loops only once, the iterative scheme reduces to the ADMM with updates in a
    Gauss-Seidel manner. If the solution from the inner iteration is assumed to be exact, the
    convergence can be deduced easily in the literature. The performance comparisons with a
    couple of recently designed solvers illustrate that the proposed methods are effective and
    competitive.
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    EEG Feature Learning Model Based on Intrinsic Time-Scale Decomposition and Adaptive Huber Loss
    YANG Li-jun, JIANG Shu-yue, WEI Xiao-ge , XIAO Yun-hai
    Chinese Quarterly Journal of Mathematics    2022, 37 (3): 281-300.   DOI: 10.13371/j.cnki.chin.q.j.m.2022.03.006
    Abstract142)      PDF(pc) (538KB)(368)       Save
    According to the World Health Organization, about 50 million people world-
    wide suffer from epilepsy. The detection and treatment of epilepsy face great challenges.
    Electroencephalogram (EEG) is a significant research object widely used in diagnosis and
    treatment of epilepsy. In this paper, an adaptive feature learning model for EEG signals
    is proposed, which combines Huber loss function with adaptive weight penalty term.
    Firstly, each EEG signal is decomposed by intrinsic time-scale decomposition. Secondly,
    the statistical index values are calculated from the instantaneous amplitude and frequency
    of every component and fed into the proposed model. Finally, the discriminative features
    learned by the proposed model are used to detect seizures. Our main innovation is to
    consider a highly flexible penalization based on Huber loss function, which can set different
    weights according to the influence of different features on epilepsy detection. Besides, the
    new model can be solved by proximal alternating direction multiplier method, which can
    effectively ensure the convergence of the algorithm. The performance of the proposed
    method is evaluated on three public EEG datasets provided by the Bonn University,
    Childrens Hospital Boston-Massachusetts Institute of Technology, and Neurological and
    Sleep Center at Hauz Khas, New Delhi(New Delhi Epilepsy data). The recognition
    accuracy on these two datasets is 98% and 99.05%, respectively, indicating the application
    value of the new model.
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